Anastomosis is the surgical joining of separate hollow organ sections. Typically, an anastomosis procedure follows surgery in which a diseased or defective section of hollow tissue is removed and the remaining end sections are to be joined. Depending on the desired anastomosis procedure, the end sections may be joined by either circular, end-to-end, end-to-side, or side-to-side organ reconstruction methods.
In a circular anastomosis procedure, the two ends of the organ sections are joined by means of a stapling instrument which drives a circular array of staples through the end section of each organ section and simultaneously cores any tissue interior of the driven circular array of staples to free the tubular passage. Examples of instruments for performing circular anastomosis of hollow organs are described in U.S. Pat. Nos. 7,303,106, 6,053,390, 5,588,579, 5,119,983, 5,005,749, 4,646,745, 4,576,167, and 4,473,077, each of which is incorporated herein in its entirety by reference. Typically, these instruments include an elongated shaft having a handle portion at a proximal end to actuate the instrument and a staple holding component disposed at a distal end. An anvil assembly including an anvil rod with attached anvil head is mounted to the distal end of the instrument adjacent the staple holding component. Opposed end portions of tissue of the hollow organ(s) to be stapled are clamped between the anvil head and the staple holding component. Typically, a first actuation mechanism is used to approximate the anvil head and the staple holding component to clamp the tissue. The clamped tissue is stapled by driving one or more staples from the staple holding component so that the ends of the staples pass through the tissue and are deformed by the anvil head. Typically, a second actuation mechanism is used to fire the staples. It is also common for an annular knife to be concurrently advanced to core tissue within the hollow organ to free a tubular passage within the organ.
Besides anastomosis of hollow organs, surgical stapling instruments for performing circular anastomosis have been used to treat internal hemorrhoids in the rectum. Typically, during use of a circular stapling instrument for hemorrhoid treatment, the anvil head and the staple holding component of the surgical stapling instrument are inserted through the anus and into the rectum with the anvil head and the staple holding component in an open or unapproximated position. Thereafter, a pursestring suture is used to pull the internal hemorrhoidal tissue towards the anvil rod. Next, the anvil head and the staple holding component are approximated to clamp the hemorrhoid tissue between the anvil head and the staple holding component. The stapling instrument is fired to remove the hemorrhoidal tissue and staple the cut tissue. In other uses for hemorrhoid surgery, the stapling instrument is used to remove tissue just above the hemorrhoids in order to pull the hemorrhoids back up inside the rectum and reduce the symptoms. The staples interrupt the blood flow of the superior hemorrhoidal arterial branches, cutting off the blood supply to the tissue, thus causing the hemorrhoids to shrink.
Some surgical stapling instruments include a safety device that prevents staples from being fired before approximation of the anvil head and the staple holding component.